Centralized control of peer-to-peer communication

ABSTRACT

Techniques for centralized control of peer-to-peer (P2P) communication and centralized control of femto cell operation are described. For centralized control of P2P communication, a designated network entity (e.g., a base station) may control P2P communication of stations (e.g., UEs) located within its coverage area. The designated network entity may receive an indication of a first station (e.g., a UE) desiring to communicate with a second station (e.g., another UE). The designated network entity may determine whether or not to select peer-to-peer communication for the first and second stations, e.g., based on the quality of their communication link. The designated network entity may assign resources to the stations if peer-to-peer communication is selected. For centralized control of femto cell operation, the designated network entity may control the operation of femto cells (e.g., may activate or deactivate femto cells) within its coverage area.

The present application claims priority to provisional U.S. ApplicationSer. No. 61/141,627, entitled “CENTRALIZED PEER-TO-PEER COMUNICATION,”filed Dec. 30, 2008, assigned to the assignee hereof and incorporatedherein by reference.

BACKGROUND

I. Field

The present disclosure relates generally to communication, and morespecifically to techniques for controlling communication in a wirelesscommunication network.

II. Background

Wireless communication networks are widely deployed to provide variouscommunication content such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting multiple users by sharing the available networkresources. Examples of such multiple-access networks include CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA)networks.

A wireless communication network may include a number of base stationsthat can support communication for a number of user equipments (UEs). AUE may communicate with a base station via the downlink and uplink. Thedownlink (or forward link) refers to the communication link from thebase station to the UE, and the uplink (or reverse link) refers to thecommunication link from the UE to the base station. The UE may also beable to communicate directly with another UE via peer-to-peercommunication. It may be desirable to control communication of the UEsuch that good performance can be achieved for both the UE and thenetwork.

SUMMARY

Techniques for centralized control of peer-to-peer (P2P) communicationand centralized control of femto cell operation are described herein. Inan aspect, for centralized control of P2P communication, a designatednetwork entity (e.g., a base station) may control P2P communication ofstations located within a coverage area. In one design, the designatednetwork entity may receive an indication of a first station (e.g., a UE)desiring to communicate with a second station (e.g., another UE or acell). The designated network entity may also receive informationindicative of the quality of the communication link between the firstand second stations. The designated network entity may determine whetheror not to select peer-to-peer communication for the first and secondstations, e.g., based on the received information. The designatednetwork entity may assign resources to the first and second stations ifpeer-to-peer communication is selected and may send informationindicative of whether peer-to-peer communication is selected, theassigned resources if any, and/or other information to the first andsecond stations.

In another aspect, for centralized control of femto cell operation, adesignated network entity (e.g., a base station) may control theoperation of femto cells within a coverage area. In one design, thedesignated network entity may receive an access request from a UE, mayidentify a femto cell capable of serving the UE, and may activate thefemto cell to serve the UE. In another design, the designated networkentity may identify a UE located within the coverage of a femto cell butunable to access the femto cell due to restricted association. Thedesignated network entity may deactivate the femto cell to allow the UEto communicate with another cell.

Various aspects and features of the disclosure are described in furtherdetail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wireless communication network.

FIG. 2 shows a process for centralized control of P2P communication.

FIG. 3 shows communication links for a base station and two stations.

FIGS. 4 and 5 show a process and an apparatus, respectively, forsupporting peer-to-peer communication by a designated network entity.

FIGS. 6 and 7 show a process and an apparatus, respectively, forcommunicating by a station.

FIGS. 8 and 9 show a process and an apparatus, respectively, forcentralized control of femto cell operation.

FIGS. 10 and 11 show another process and another apparatus,respectively, for centralized control of femto cell operation.

FIG. 12 shows a design of a base station and two stations.

DETAILED DESCRIPTION

The techniques described herein may be used for various wirelesscommunication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as Evolved UTRA(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA and E-UTRA are part ofUniversal Mobile Telecommunication System (UMTS). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS thatuse E-UTRA, which employs OFDMA on the downlink and SC-FDMA on theuplink. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies.

FIG. 1 shows a wireless communication network 100, which may be awireless wide area network (WWAN). Network 100 may be a cellular networksuch as an LTE network or some other WWAN. Network 100 may include anumber of evolved Node Bs (eNBs) and other network entities that cansupport communication for a number of UEs. An eNB may be a station thatcommunicates with the UEs and may also be referred to as a base station,a Node B, an access point, etc. An eNB may provide communicationcoverage for a particular geographic area. In 3GPP, the term “cell” canrefer to a coverage area of an eNB and/or an eNB subsystem serving thiscoverage area, depending on the context in which the term is used. AneNB may support one or multiple (e.g., three) cells.

An eNB may provide communication coverage for a macro cell, a pico cell,a femto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG)). A femto cell may also be aLocal IP Access (LIPA)-only femto cell, which may not allow UEs toconnect to the Internet but may have local traffic originating in thefemto cell itself. For example, a store may have a LIPA-only femto cellthat sends coupons to cellular phones in its vicinity. An eNB for amacro cell may be referred to as a macro eNB. An eNB for a pico cell maybe referred to as a pico eNB. An eNB for a femto cell may be referred toas a femto eNB or a home eNB. In FIG. 1, an eNB 110 may be a macro eNBfor a macro cell 102, an eNB 114 may be a pico eNB for a pico cell 104,and an eNB 116 may be a femto eNB for a femto cell 106. The terms “basestation”, “eNB”, and “cell” may be used interchangeably.

A relay station 118 may be a station that receives a transmission ofdata and/or other information from an upstream station (e.g., eNB 110 ora UE 128) and sends a transmission of the data and/or other informationto a downstream station (e.g., UE 128 or eNB 110). A relay station mayalso be a UE that relays transmissions for other UEs. A relay stationmay also be referred to as a relay, a relay eNB, a relay UE, etc. InFIG. 1, relay station 118 may communicate with UE 128 via an access linkand may communicate with eNB 110 via a backhaul link to supportcommunication between UE 128 and eNB 110.

UEs 120 to 128 may be dispersed throughout the wireless network, andeach UE may be stationary or mobile. A UE may also be referred to as aterminal, a mobile station, a subscriber unit, a station, etc. A UE maybe a cellular phone, a personal digital assistant (PDA), a wirelessmodem, a wireless communication device, a handheld device, a laptopcomputer, a cordless phone, a wireless local loop (WLL) station, etc. AUE may communicate with eNBs and/or relay stations in a WWAN. A UE mayalso communicate with access points in a wireless local area network(WLAN), which may utilize IEEE 802.11 (Wi-Fi) or some other radiotechnology. A UE may also communicate with other devices in a wirelesspersonal area network (WPAN), which may utilize Bluetooth or some otherradio technology.

A network controller 140 may couple to a set of eNBs and may providecoordination and control for these eNBs. Network controller 140 maycomprise a Radio Network Controller (RNC), a Mobile Switching Center(MSC), a Mobility Management Entity (MME), a Serving Gateway (SGW), aPacket Data Network (PDN) Gateway (PGW), and/or some other networkentity.

In general, a macro eNB may communicate with any number of stations. Amacro eNB may also control communication for stations within itscoverage. A station may be a UE, a relay station, a femto eNB, a picoeNB, a peripheral device such as a printer, etc. For simplicity, in muchof the description below, a macro eNB may be referred to as simply aneNB.

Network 100 may support peer-to-peer (P2P) communication betweenstations. For P2P communication, two stations (e.g., UEs 120 and 122)may communicate directly with each other without communicating with aneNB in a WWAN. P2P communication may reduce the load on the WWAN forlocal communications between the stations. P2P communication between UEsmay also allow one of the UEs to act as a relay for the other UE,thereby enabling the other UE to connect to an eNB.

In an aspect, centralized control of P2P communication may be supportedto improve performance. For centralized control of P2P communication, adesignated network entity may control P2P communication for stationslocated within its coverage area. This coverage area may be a cell, acluster of cells, etc. The designated network entity may control variousaspects of P2P communication such as selection of stations for P2Pcommunication, resource allocation, interference management, etc. In onedesign, the designated network entity may be an eNB that can control P2Pcommunication for stations within its coverage. In other designs, thedesignated network entity may be a network entity such as an MME thatcan control P2P communication for stations in a cluster of cells.

FIG. 2 shows a design of a process 200 for centralized control of P2Pcommunication. For clarity, process 200 assumes that the designednetwork entity is an eNB, e.g., eNB 110 in FIG. 1. The eNB may receivean indication that two stations (e.g., UEs 120 and 122 in FIG. 1) desireto communicate with each other (block 212). The eNB may obtaininformation indicative of the quality of the communication link betweenthe two stations (block 214). For example, a user of a first UE may callanother user of a second UE, and the call may be initially placed viathe eNB. The first UE may send the UE identity (ID) of the second UE andinformation indicative of the quality of the communication link betweenthe first and second UEs to the eNB.

The eNB may determine whether it is better to allow the two stations tocommunicate directly with each other or via the WWAN (block 216). TheeNB may make this determination based on the information indicative ofthe link quality and/or other information. For example, if the twostations are far from each other or are located in differentcells/geographic areas, then the eNB may determine that it would bebetter for the stations to communicate via the WWAN (e.g., using WWANresources). Conversely, if the two stations are sufficiently close toeach other, then it may be more beneficial for these stations tocommunicate directly with each other in order to reduce usage of WWANresources for the communication.

If P2P communication is not selected for the two stations, as determinedin block 218, then the eNB may direct the two stations to communicatevia the WWAN (block 220). Conversely, if P2P communication is selectedfor the two stations, as determined in block 218, then the eNB mayassign resources to the two stations for P2P communication (block 222).The assigned resources may comprise time-frequency resources (orbandwidth), etc. The eNB may also assign transmit power levels to thetwo stations for P2P communication. In one design, both downlink anduplink resources may be reserved for P2P communication and may not beused for WWAN communication (i.e., communication with the WWAN). Thismay be similar to a macro eNB reserving some resources for pico cells toenable cell splitting gains. In this design, one station may act as aneNB and may transmit using downlink resources, and the other station mayact as a UE and may transmit using uplink resources. This design mayallow the two stations to communicate using the same radio technology(e.g., LTE) used for WWAN communication. In another design, resourcesfor only one direction (e.g., the uplink) may be assigned for P2Pcommunication. In this design, the two stations may communicatepeer-to-peer on the uplink using time division duplexing (TDD).

The eNB may send scheduling information indicative of its decision andthe assigned resources, if any, to the stations (block 224). The eNB maysend the scheduling information to each station directly or to theoriginating station, which may forward the information to the otherstation.

The stations may receive the scheduling information from the eNB and maycommunicate peer-to-peer, if selected, using the assigned resources. Thestations may slowly increase their transmit power levels to the assignedpower levels in order to avoid causing sudden increase in interference,which may adversely impact the operation of nearby stations. Thestations may communicate peer-to-peer using either the same radiotechnology used for WWAN communication (e.g., LTE-A) or a differentradio technology (e.g., FlashLinQ, which is designed especially for P2Pcommunication).

The two stations may be of the same type, e.g., two UEs. The twostations may also be of different types. For example, one station may bea UE whereas the other station may be a femto cell. In this case, theeNB may instruct the femto cell (or home eNB) to start transmitting whenthe UE becomes active, or based on the geographic or radio location ofthe UE, or based on prior geographic/radio history of the UE.

In general, P2P communication may be beneficial when it would result inless interference to the network as compared to WWAN communication. Adecision on whether or not to use P2P communication for two stations maybe made based on an estimated amount of interference caused by the twostations for P2P communication versus an estimated amount ofinterference caused by the two stations for WWAN communication. Forcommunication with one station acting as a relay, the total interferencedue to both the access link and the backhaul link may be taken intoconsideration. The amount of interference caused by P2P communicationmay be roughly estimated based on the quality of the communication linkbetween the two stations.

FIG. 3 shows communication links for two stations A and B and an eNB.The communication link between stations A and B may be referred to aslink (A, B), the communication link between station A and the eNB may bereferred to as link (A, X), and the communication link between station Band the eNB may be referred to as link (B, X). The amount ofinterference caused by P2P communication via link (A, B) may bedependent on the quality of this link, which may be estimated in variousmanners.

In one design, the quality of link (A, B) may be determined based onpilot measurements and/or interference measurements for this link. Forexample, station A may transmit a reference signal or pilot, and stationB may measure the received signal strength of the reference signal fromstation A. Alternatively or additionally, station A may measure thereceived signal strength of a reference signal from station B.

In another design, the quality of link (A, B) may be determined based onthe estimated distance between stations A and B. The distance betweenstations A and B may be estimated based on measurements of round tripdelay (RTD) between these stations. The distance between stations A andB may also be determined based on the locations of these stations. Thelocation of each station may be estimated based on a satellite-basedpositioning method or a network-based positioning method. In any case,the distance between stations A and B may be determined based on theirestimated locations.

In yet another design, the quality of link (A, B) may be determinedbased on measurements made by both stations A and B for the same set ofone or more transmitters. For example, each station may make pilotmeasurements for one or more cells. If the measurements made by stationA somewhat match the measurements made by station B, then the twostations may be deemed to be in close proximity to one another and henceobserve similar signals.

The quality of link (A, B) may also be determined in other manners. Ingeneral, the link quality may be determined based on one or moresuitable criteria/parameters.

In one design, the quality of link (A, B) may be compared against athreshold. If the link quality exceeds the threshold, then P2Pcommunication may be selected for the two stations. Otherwise, WWANcommunication may be selected for the two stations. The link quality maybe assigned a value to facilitate comparison against the threshold. Thethreshold may be selected based on a target amount of interference dueto P2P communication and/or other considerations.

In another design, the quality of link (A, B) may be compared againstthe overall quality of link (A, X) and link (B, X). P2P communicationmay be selected if the P2P link is sufficiently better than the WWANlinks, and WWAN communication may be selected otherwise.

FIG. 3 shows a simple example with two stations desiring to communicatewith one another. In general, any number of pairs of stations may desireto communicate with one another. Each pair of stations may causeinterference to other pairs of stations. A scheduling algorithm maydetermine which pairs of stations should communicate peer-to-peer andwhat resources to assign to these pairs of stations.

In one scheduling design, a connectivity graph of all stations desiringto communicate may be formed. The connectivity graph may include (i) anode for each station desiring to communicate with another station and(ii) an edge or line between each pair of nodes for stations withinterference above a particular threshold. Each edge may also beassociated with a value indicative of the amount of interference forthat edge in order to allow for “soft” edges. The edges may bedetermined based on pilot reports received from the stations and/orother information described above. The graph may represent interferenceconditions for all stations desiring to communicate with other stations.

The graph may be colored to maximize capacity. Coloring refers toassignment of resources to stations for P2P communication. Differentcolors may be used to denote different resources (e.g., different setsof subcarriers) that may be assigned to the stations. For example, a setof colors D1, D2, D3, etc. may be defined for downlink resources fornodes acting as eNBs, and another set of colors U1, U2, U3, etc. may bedefined for uplink resources for nodes acting as UEs. The downlink anduplink resources may be for (i) different frequency channels withfrequency division duplexing (FDD) or (ii) the same frequency channelwith time division duplexing (TDD). For TDD, the D and U resources(e.g., time slots) may both be for the uplink but may occur at differenttimes. For a given P2P link between a pair of nodes, one node may becolored with Dn, and the other node may be colored with Um. Coloring mayalso be performed dynamically, e.g., for nodes that switch betweendownlink and uplink depending on bandwidth needs.

In one design, a greedy algorithm may be used for coloring to maximizecapacity. For the greedy algorithm, a node with the highest degree and acorresponding peer node may be removed from the graph. The degree of anode/device is given by the number of edges connected to that node andcorresponds to the number of peer devices with which the node/device hasinterference conditions. The highest degree node may interfere with alot of P2P communication and may thus adversely impact cell-splittinggains. The stations corresponding to the removed nodes may communicatevia the WWAN instead of peer-to-peer. After removing the pair of highestdegree nodes from the graph, the smallest number of colors (orresources) that can be used for the graph may be determined. This graphcoloring may be NP-complete, and various algorithms may be used tosimplify the coloring or resource assignment. After coloring, thecapacity or achievable data rates of the nodes in the graph may bedetermined based on the colors assigned to the nodes and using asuitable metric.

The process described above may be repeated iteratively. Another pair ofnodes with the highest degree may be removed from the graph, colors maybe assigned to the remaining nodes in the graph, and the capacity of thenodes may be determined based on the assigned colors. If the capacityfor the current iteration is higher than the capacity for the previousiteration, then the process may be repeated once more. The process maybe terminated when removing nodes does not improve capacity. Thestations corresponding to the nodes in the graph with the highestcapacity may be selected for P2P communication. The resourcescorresponding to the colors for these nodes may be assigned to theselected stations.

The connectivity graph may be defined for stations in a given coveragearea, which may cover a single macro cell, a cluster of macro cells,etc. This may result in boundary conditions. Appropriate message passingalgorithms for the connectivity graph may be used for resourcepartitioning.

In one design, centralized control may be used for P2P communicationbetween UEs as well as P2P communication between UEs and non-UEs, e.g.,between a UE and a femto cell. In another design, centralized controlmay be used for P2P communication between UEs, and distributed controlmay be used for P2P communication between UEs and non-UEs. Forcentralized control, a designated network entity (e.g., a master eNB)may make all resource allocation decisions. For distributed control,resource allocation decisions may be made by different entities such asfemto cells, e.g., either autonomously or via cooperation using messageexchanges. The number of UEs desiring P2P communication in a macro cellmay be small, and these UEs may fall back to WWAN communication. Suchfallback may not be available for femto cells, which may favordistributed control. In yet another design, semi-centralized control maybe used. In this design, some scheduling (e.g., for intra-cell P2Pcommunication) may be performed in a centralized manner (e.g., by aneNB), while other scheduling (e.g., for inter-cell P2P communication)may be performed in a distributed manner.

An eNB may control P2P communication for stations within its coverage.The eNB may also instruct some stations to act as relays for otherstations and may assign resources to these stations. The eNB maydetermine which stations to select as relay stations based on variouscriteria such as capacity, interference, UE power and complexity, UEmobility, etc. For example, the eNB may select stations that would causethe least amount of interference on both the access link and thebackhaul link. The eNB may also select multiple stations to act as relaystations for a single station.

In another aspect, centralized control of femto cell operation may besupported to improve performance. A designated network entity maycontrol the operation of femto cells within a coverage area. In onedesign, the designated network entity may be an eNB controlling femtocells within its coverage area. In other designs, the designated networkentity may be a network entity such as an MME that can control femtocells in a cluster of macro cells.

In one design, an eNB may activate a femto cell for communication with aUE when the UE attempts to access the eNB. This femto cell may be a cellthat the UE can access. For example, in FIG. 1, eNB 110 may activatefemto cell 116 for communication with UE 126. The eNB may identify thefemto cell based on a UE ID of the UE and a mapping of UE IDs to femtocells. This mapping may be generated via registration by the femto cellsand/or the UEs, via reports from the femto cells and/or the UEs, etc.The eNB may also identify the femto cell based on signaling from the UE,which may specifically identify the femto cell. The eNB may alsoidentify the femto cell based on geographic locations of the UE and thefemto cell, which may be estimated in various manners as describedabove. The eNB may also identify the femto cell based on radio location,e.g., based on the femto cell having similar pilot strength measurementsas the UE. The eNB may also identify the femto cell based on pasthistory of communication between the femto cell and the UE. Past historyinformation may be gathered by having femto cells and/or UEs reporttheir communication to the eNB. The eNB may also identify the femto cellthat can serve the UE based on other information.

The eNB may assign resources to the femto cell for communication withthe UE. The femto cell may raise its transmit power slowly in order toprevent connection drops for the UE as well as other UEs in thevicinity.

Femto cells may be activated, as needed, to support communication forUEs, as described above. The activated femto cells may be assignedresources (e.g., via efficient coloring) to support communication withthe UEs. Significant reduction in interference may be achieved by havingonly the activated femto cells transmit. The activated femto cells mayalso utilize less resources (e.g., less bandwidth). These factors mayimprove overall capacity and performance Centralized control may alsoenable the eNB to efficiently manage interference conditions andresource usage.

Centralized control of femto cell operation may be able to mitigatecoverage holes for UEs. A UE may be located within the coverage of afemto cell that the UE cannot access due to restricted association. Ifthe femto cell transmits continually even when it is not serving anyUEs, then the UE may observe excessive interference from the femto celland may be unable to communicate with a macro cell or another femtocell. The UE would then be within a coverage hole due to the femto cell.The eNB may deactivate the femto cell in order to mitigate interferenceto the UE, which may then allow the UE to communicate with another cell.

In one design, the eNB may deactivate the femto cell if at least onerestricted UE, which cannot access the femto cell, is located within thecoverage of the femto cell. In another design, the eNB may allow thefemto cell to be active when the restricted UE(s) are idle and maydeactivate the femto cell when any of the idle UEs become active. TheeNB may also control the femto cell in other manners. Some resources maybe reserved to enable the eNB to communicate with (e.g., to send pagesto) the restricted UE(s).

A femto cell may have one or more restricted UEs within its coverage,and the restricted UE(s) may be outside of macro coverage. This may bethe case, e.g., when the femto cell is deployed indoor. Deactivating thefemto cell in this scenario may not provide benefits to the restrictedUE(s). In one design, the femto cell may turn on periodically and maygather reports sent by UEs. If the reports indicate the presence of oneor more macro cells, then the femto cell can shut down. Otherwise, thefemto cell can stay on.

FIG. 4 shows a design of a process 400 for supporting peer-to-peercommunication. Process 400 may be performed by a network entity, whichmay be a base station, a network controller, etc. The network entity mayreceive an indication of a first station desiring to communicate with asecond station (block 412). The network entity may also receiveinformation indicative of the quality of a communication link betweenthe first and second stations (block 414). This information may comprisepilot measurements, interference measurements, RTD measurements,location information, etc., or a combination thereof.

The network entity may determine whether or not to select peer-to-peercommunication for the first and second stations, e.g., based on thereceived information (block 416). In one design, the network entity maycompare the quality of the communication link between the first andsecond stations against a threshold and may select peer-to-peercommunication for these stations if the quality of the communicationlink exceeds the threshold. The network entity may also selectpeer-to-peer communication or WWAN communication for the first andsecond stations in other manners and/or based on other selectioncriteria.

The network entity may assign resources to the first and second stationsif peer-to-peer communication is selected (block 418). The assignedresources may comprise time and/or frequency resources, transmit powerlevels, etc. The network entity may also designate (i) one station tooperate as a base station and transmit on the downlink and receive onthe uplink and (ii) the other station to operate as a UE and transmit onthe uplink and receive on the downlink. The network entity may alsodetermine whether to select the second station as a relay station forthe first station. The network entity may send information indicative of(i) whether peer-to-peer communication is selected for the first andsecond stations, (ii) the assigned resources if peer-to-peercommunication is selected, (iii) which station will as act a basestation, and/or (iv) other information for the first and second stations(block 420). Peer-to-peer communication may occur on frequency spectrumnot used for WWAN communication or on frequency spectrum used for WWANcommunication. The first and second stations may transmit using TDD(e.g., on uplink frequency spectrum) or FDD (e.g., on both downlink anduplink frequency spectrum) for peer-to-peer communication.

In one design, the network entity may be a base station that can controlpeer-to-peer communication for UEs within the coverage of the basestation. The first and second stations may be two UEs. Alternatively,one station may be a UE while the other station may be a femto cell.

FIG. 5 shows a design of an apparatus 500 for supporting peer-to-peercommunication by a network entity. Apparatus 500 includes a module 512to receive an indication of a first station desiring to communicate witha second station, a module 514 to receive information indicative of thequality of a communication link between the first and second stations, amodule 516 to determine whether or not to select peer-to-peercommunication for the first and second stations, e.g., based on thereceived information, a module 518 to assign resources to the first andsecond stations if peer-to-peer communication is selected, and a module520 to send information indicative of whether peer-to-peer communicationis selected, the assigned resources if any, and/or other information forthe first and second stations.

FIG. 6 shows a design of a process 600 for wireless communication.Process 600 may be performed by a first station, which may be a UE orsome other entity. The first station may send to a network entity anindication of a desire to communicate with a second station (block 612).The first station may also send information indicative of the quality ofa communication link between the first and second stations (block 614).The first station may receive, from the network entity, informationindicative of (i) whether or not to use peer-to-peer communicationbetween the first and second stations, (ii) an assignment of resourcesif peer-to-peer communication is selected, and/or (iii) otherinformation (block 616). The network entity may determine whether or notto use peer-to-peer communication based on the information sent by thefirst station. The first station may communicate directly with thesecond station based on the assigned resources if peer-to-peercommunication is selected (block 618). The first station may communicatewith the second station via a base station/WWAN if peer-to-peercommunication is not selected (block 620).

FIG. 7 shows a design of an apparatus 700 for wireless communication.Apparatus 700 includes a module 712 to send, from a first station to anetwork entity, an indication of the first station desiring tocommunicate with a second station, a module 714 to send informationindicative of the quality of a communication link between the first andsecond stations, a module 716 to receive, from the network entity,information indicative of whether or not to use peer-to-peercommunication between the first and second stations, an assignment ofresources if any, and/or other information, a module 718 to communicatedirectly with the second station based on the assigned resources ifpeer-to-peer communication is selected, and a module 720 to communicatewith the second station via a base station if peer-to-peer communicationis not selected.

FIG. 8 shows a design of a process 800 for centralized control of femtocell operation. Process 800 may be performed by a network entity, whichmay be a base station, a network controller, etc. The network entity mayreceive an access request from a UE (block 812). The network entity mayidentify a femto cell capable of serving the UE (block 814). The femtocell may be identified based on a UE ID of the UE, information receivedfrom the UE, geographic locations of the UE and the femto cell, radiolocations of the UE and the femto cell, past history of communicationbetween the UE and the femto cell, some other information, or anycombination thereof. The network entity may activate the femto cell toserve the UE (block 816).

FIG. 9 shows a design of an apparatus 900 for centralized control offemto cell operation. Apparatus 900 includes a module 912 to receive anaccess request from a UE, a module 914 to identify a femto cell capableof serving the UE, and a module 916 to activate the femto cell to servethe UE.

FIG. 10 shows a design of a process 1000 for centralized control offemto cell operation. Process 1000 may be performed by a network entity,which may be a base station, a network controller, etc. The networkentity may identify a UE located within the coverage of a femto cell butunable to access the femto cell due to restricted association (block1012). The network entity may deactivate the femto cell to allow the UEto communicate with another cell (block 1014). The network entity mayallow the femto cell to operate if the UE is not within coverage of anymacro cell. The network entity may also allow the femto cell to operateif the UE is in an idle mode and may deactivate the femto cell if the UEis not in the idle mode.

FIG. 11 shows a design of an apparatus 1100 for centralized control offemto cell operation. Apparatus 1100 includes a module 1112 to identifya UE located within the coverage of a femto cell but unable to accessthe femto cell due to restricted association, and a module 1114 todeactivate the femto cell to allow the UE to communicate with anothercell.

The modules in FIGS. 5, 7, 9 and 11 may comprise processors, electronicdevices, hardware devices, electronic components, logical circuits,memories, software codes, firmware codes, etc., or any combinationthereof.

For clarity, much of the description above refers to P2P communicationand WWAN communication. In general, the techniques described herein maybe applicable for P2P communication and (i) WWAN communication betweenstations and base stations/eNBs, (ii) WLAN communication betweenstations and access points (e.g., using Wi-Fi), and (iii) WPANcommunication between stations and devices (e.g., using Bluetooth).Hence, references to WWAN communication in the description above may bereplaced with WWAN communication, WLAN communication, and/or WPANcommunication.

FIG. 12 shows a block diagram of a design of base station/eNB 110 andtwo stations 120 and 122. Each station may be a UE or some other entity.At base station 110, a transmit (TX) data processor 1210 may receivedata to send to stations and may process (e.g., encode and modulate) thedata for each station in accordance with one or more modulation andcoding schemes for that station to obtain data symbols. Processor 1210may also process control information to obtain control symbols, generatereference symbols for reference signal, and multiplex the data symbols,the control symbols, and the reference symbols. Processor 1210 mayfurther process the multiplexed symbols (e.g., for OFDM, etc.) togenerate output samples. A transmitter (TMTR) 1212 may condition (e.g.,convert to analog, amplify, filter, and upconvert) the output samples togenerate a downlink signal, which may be transmitted to stations 120 and122.

At station 120, the downlink signal from base station 110 may bereceived and provided to a receiver (RCVR) 1236. Receiver 1236 maycondition (e.g., filter, amplify, downconvert, and digitize) thereceived signal and provide input samples. A receive (RX) data processor1238 may process the input samples (e.g., for OFDM, etc.) to obtainreceived symbols. Processor 1238 may further process (e.g., demodulateand decode) the received symbols to recover data and control informationsent to station 120. On the uplink, a TX data processor 1230 may process(e.g., encode and modulate) data and control information to be sent bystation 120 to obtain data symbols and control symbols. Processor 1230may also generate reference symbols, multiplex the data and controlsymbols with the reference symbols, and process the multiplexed symbol(e.g., for SC-FDMA, etc.) to obtain output samples. A transmitter 1232may condition the output samples and generate an uplink signal, whichmay be transmitted to base station 110 and/or station 122.

At base station 110, the uplink signal from station 120 may be receivedand conditioned by a receiver 1216, and processed by an RX dataprocessor 1218 to recover the data and control information sent bystation 120. A controller/processor 1220 may control data transmissionon the downlink and uplink.

Station 120 may also communicate peer-to-peer with station 122. Data,control information, and reference signals may be processed by TX dataprocessor 1230, conditioned by transmitter 1232, and transmitted tostation 122. A P2P signal from station 122 may be received andconditioned by receiver 1236 and processed by RX data processor 1230 torecover data, control information, and reference signals sent by station122.

Station 122 includes a receiver 1252, a transmitter 1258, an RX dataprocessor 1254, a TX data processor 1256, a controller/processor 1260,and a memory 1262 that may operate in similar manner as thecorresponding units at station 120.

Controllers/processors 1220, 1240 and 1260 may control the operation atbase station 110, station 120, and station 122, respectively.Controller/processor 1220 may also perform or direct process 200 in FIG.2, process 400 in FIG. 4, process 800 in FIG. 8, process 1000 in FIG.10, and/or other processes for the techniques described herein.Controllers/processors 1240 and 1260 may each perform or direct process800 in FIG. 8 and/or other processes for the techniques describedherein. Memories 1222, 1242 and 1262 may store data and program codesfor base station 110, station 120, and station 122, respectively.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. An apparatus for wireless communication,comprising: a memory; and at least one processor coupled to the memoryand configured to: send an indication of a first station desiring tocommunicate with a second station, the indication being sent from thefirst station to a network entity; send information indicative of aquality of a communication link between the first station and the secondstation, the information being sent from the first station to thenetwork entity and including one or more pilot measurements; receive,from the network entity, information indicative of a decision forwhether or not to use peer-to-peer communication between the first andsecond stations, the information including an assignment of one or morewireless wide area network (WWAN) resources for the first station by thenetwork entity, the decision based on an estimated amount ofinterference that would be caused by the first station and the secondstation if in peer-to-peer communication and an estimated amount ofinterference caused by the first station and the second station if inWWAN communication; and communicate with the second station in responseto a reception of information indicative of a selection of peer-to-peercommunication from the network entity and based on the assignment of oneor more WWAN resources.
 2. The apparatus of claim 1, wherein tocommunicate with the second station in response to the reception ofinformation indicative of a selection of peer-to-peer communication fromthe network entity and based on the assignment of one or more WWANresources, the at least one processor is further configured tocommunicate directly with the second station.
 3. The apparatus of claim1, wherein the at least one processor is further configured tocommunicate with the second station via the network entity in responseto a reception of information indicative of foregoing selection ofpeer-to-peer communication from the network entity.
 4. The apparatus ofclaim 1, wherein to send information indicative of the quality of thecommunication link between the first station and the second station, theat least one processor is further configured to send informationindicative of interference at the first station.
 5. A non-transitorycomputer-readable medium storing computer executable code, comprising:code for causing at least one computer to send an indication of a firststation desiring to communicate with a second station, the indicationbeing sent from the first station to a network entity; code for causingat least one computer to send information indicative of a quality of acommunication link between the first station and the second station, theinformation being sent from the first station to the network entity andincluding one or more pilot measurements; code for causing the at leastone computer to receive, from the network entity, information indicativeof a decision for whether or not to use peer-to-peer communicationbetween the first and second stations, the information including anassignment of one or more wireless wide area network (WWAN) resourcesfor the first station by the network entity, the decision based on acomparison of an estimated amount of interference that would be causedby the first station and the second station if in peer-to-peercommunication and an estimated amount of interference caused by thefirst station and the second station if in WWAN communication; and codefor causing the at least one computer to communicate with the secondstation in response to receiving information indicative of a selectionof peer-to-peer communication from the network entity and based on theassignment of one or more WWAN resources.
 6. A method of wirelesscommunication, comprising: sending an indication of a first stationdesiring to communicate with a second station, the indication being sentfrom the first station to a network entity; sending informationindicative of a quality of a communication link between the firststation and the second station, the information being sent from thefirst station to the network entity and including one or more pilotmeasurements; receiving, from the network entity, information indicativeof a decision for whether or not to use peer-to-peer communicationbetween the first and second stations, the information including anassignment of one or more wireless wide area network (WWAN) resourcesfor the first station by the network entity, the decision based on anestimated amount of interference that would be caused by the firststation and the second station if in peer-to-peer communication and anestimated amount of interference caused by the first station and thesecond station if in WWAN communication; and communicating with thesecond station in response to a reception of information indicative of aselection of peer-to-peer communication from the network entity andbased on the assignment of one or more WWAN resources.
 7. The method ofclaim 6, wherein communicating with the second station in response tothe reception of information indicative of a selection of peer-to-peercommunication from the network entity and based on the assignment of oneor more WWAN resources includes communicating directly with the secondstation.
 8. The method of claim 6, further comprising communicating withthe second station via the network entity in response to a reception ofinformation indicative of foregoing selection of peer-to-peercommunication from the network entity.
 9. The method of claim 6, whereinsending information indicative of the quality of the communication linkbetween the first station and the second station includes sendinginformation indicative of interference at the first station.
 10. Themethod of claim 6, wherein the one or more WWAN resources include atleast a transmit power level for the first station.
 11. The method ofclaim 6, wherein the assignment of the one or more WWAN resources forthe first station includes an assignment of one or more first resourcesfor transmission according to time division duplexing (TDD) on an uplinkcommunication channel or one or more second resources for communicationaccording to frequency division duplexing (FDD) on one or both of adownlink or uplink communication channel.